Rivet panel (bellow) for easy-o end unit rivet structure

ABSTRACT

An improved pull tab mounting arrangement provides an movable fulcrum to facilitate opening a self-opening can. An expandable pleat is formed in the end panel at the base of the tab-attaching rivet and the tab is mounted with its nose portion in spaced relation above and radially inward of the opening score line. As the finger ring portion of the tab is lifted, the pleat unfolds, allowing both the rivet and the tab to travel upwardly and outwardly to bring the tab nose into contact with the score line. This displacement moves the fulcrum point of the tab toward the nose portion and away from the finger ring portion, thereby providing increased leverage and reducing the effort required to fracture the score line. In addition, the stress placed on the tab and the end panel during opening is reduced, thereby permitting the use of thinner gauge metal for these members. Further, spacing of the nose portion and the score line reduces the probability that mishandling of the container will result in an unintentional fracture of the score.

United States Patent [1 1 Patel [54] RIVET PANEL (BELLOW) FOR EASY-O ENDUNIT RIVET STRUCTURE [75] Inventor: Anilkumar U. Patel, Summit, Ill.

[73] Assignee: Continental Can Company, Inc.,

New York, NY.

22 Filed: Feb. 10, 1975 [2]] Appl. No.: 548,321

Primary Examiner-George T. Hall Attorney, Agent, or Firm-John J.Kowalik; Joseph E. Kerwin; William A. Dittmann Oct. 28, 1975 [57]ABSTRACT An improved pull tab mounting arrangement provides an movablefulcrum to facilitate opening a selfopening can. An expandable pleat isformed in the end panel at the base of the tab-attaching rivet and thetab is mounted with its nose portion in spaced relation above andradially inward of the opening score line. As the finger ring portion ofthe tab is lifted, the pleat unfolds, allowing both the rivet and thetab to travel upwardly and outwardly to bring the tab nose into contactwith the score line. This displacement moves the fulcrum point of thetab toward the nose portion and away from the finger ring portion,thereby providing increased leverage and reducing the effort required tofracture the score line In addition, the stress placed on the tab andthe end panel during opening is reduced, thereby permitting the use ofthinner gauge metal for these members. Further, spacing of the noseportion and the score line reduces the probability that mishandling ofthe container will result in an unintentional fracture of the score.

11 Claims, 4 Drawing Figures U.S. Patent Oct. 28, 1975 Sheet 1 of23,915,334

SUMMARY OF THE INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENT Inkeeping with the present invention, there is pro- This invention relatesto a container having a portion vided an easy-open end closurecomprising a metal end of its wall weakened to serve as a tear strip andhaving a tab attached to the tear strip to serve as a lever forinitiating the severing operation.

In general, the invention is directed to two problems which have come tothe fore with widespread acceptance of this type of container. Oneproblem is to make it easier to lift the tab to initiate severance ofthe tear strip. The second problem is to prevent the unintentionalfracturing of the opening score line which may occur as the result ofmishandling of the container.

It is, therefore, one of the primary objects of the present invention toprovide an improved pull tab mounting arrangement which will facilitatethe opening of a selfopening container. This is accomplished byincreasing the leverage afforded by the pull tab. More specifically, thetab is mounted such that lifting of the tab causes the fulcrum point tobe displaced toward the nose portion and away from the finger ringportion, thereby providing the user an increase in mechanical advantage.

It is a further object of this invention to provide an improved pull tabmounting arrangement which will reduce the probability that mishandlingof the container will result in unintentional fracturing of the openingscore line. This is accomplished by mounting the tab such that its noseportion is maintained in spaced relation with the score line, therebypreventing minor displacements of the tab from resulting in a score linefracture.

It is another object of this invention to provide an improved pull tabmounting arrangement which will permit the use of thinner gauge metal inthe fabrication of the pull tab and end panel. This is accomplished bymounting the pull tab so as to reduce the stress placed on these membersduring opening. Specifically, the stress on the end panel in the regionimmediately adjacent to the rivet is reduced by the use of an expandablebellow which allows controlled distortion of the metal in this area.

It is still another object to provide an improved pull tab mountingarrangement which requires minimal modification of existing productiontooling.

It is yet another object to provide an improved pull tab mountingarrangement which may be produced economically and with a wide degree ofmanufacturing latitude.

BRIEF DESCRIPTION OF THE DRAWINGS The various features and advantages ofthe tab mounting arrangement of this invention will be more apparentfrom the following detailed description when considered in connectionwith the accompanying drawing wherein:

FIG. 1 is a cross-sectional view of an end closure with the improved tabmounting arrangement, illustrating the unopened condition.

FIG. 2 is a cross-sectional view similar to FIG. 1, illustrating thepartially opened condition.

FIG. 3 is a cross-sectional view of a conventional end closure.

FIG. 4 is a cross-sectional view similar to FIG. 3, illustratingdistortion due to opening stresses.

panel 1, a rivet 2 integrally formed in said end panel and a metal pulltab 3 fixedly attached to said end panel 1 by said rivet 2. A score line4 is formed in the end panel 1 and defines an opening flap 5 therein.

In the standard easy-open closure (FIG. 3), which lacks a pleat 6,opening is accomplished by vertically displacing the tab 3, therebypivoting said tab 3 about said rivet 1 and imposing a downward force onthe tab nose portion 3a, said force resulting in the breaking of saidend panel 1 along said score line 4 beneath said nose portion3a.Continued upward displacement of said tab 3 results in controlledtearing of said end panel 1 along said score line 4, the opening flap 5defined by said score 4 being bent down and away from said end panel 1,thereby establishing an opening in said end panel 1.

The fulcrum point 7 of the conventional easy-open closure is located onthe interface between the tab 3 and the rivet head 2a at the pointfurthest between the tab 3 and the 3a. As the tab finger ring portion 3bis lifted, an upward force is impressed on the rivet 2 and the end panel1 in the area immediately adjacent to the fulcrum point 7. Thisstressing of the end panel 1 and the rivet 2 necessitates the use of athickness of metal with sufficient strength and rigidity to resistdeformation or tearing during opening of the container. Further, thisconfiguration minimizes the length of the lever arm and maximizes thelength of the load arm and, consequently, places the maximum stress onthe tab 3. This necessitates the use of a thickness of metal for the tab3 which will resist bending during opening of the container. Theinefficient lever arrangement also results in the requirement ofconsiderable effort to lift the tab 3 sufficiently far to effectfracture of the score line 4.

In the improved tab mounting arrangement of the present invention(FIG. 1) an expandable pleat 6 is formed in the end panel 1 concentricwith and immediately adjacent to the rivet 2. The pleat 6 comprises twosubstantially parallel, concentric sidewalls 6a depending from the endpanel I and a connecting U-shaped bight portion 6b. The tab nose portion3a is held in spaced relation above and radially inward of the scoreline 4, rather than in close contact with the score line as in thestandard end closure.

As the finger ring portion 3b is lifted, the pleat 6 unfolds evertingoutwardly with the unfolded sidewalls 6a projecting above the plane ofthe end panel 1 and causing displacement of the fulcrum point 7 radiallyoutwardly upwardly toward the score line 4 (FIG. 2), thereby bringingthe nose portion 3a into close contact with the score line 4. After thepleat 6 has unfolded, the end closure is opened in the conventionalmanner as described hereinabove. However, the fulcrum displacement hasresulted in an increase in the length of the load arm which in turnresults in a decrease in the stress loading on the tab 3 during openingof the container. Further, the effort required to open the container hasbeen reduced.

The expansion of the pleat 6 also serves to relieve the stresses on therivet 2 and the end panel 1 by allowing controlled distortion thereof.These stress reductions allow the fabrication of the tab 3 and the endpanel 1 from a thinner gauge metal.

The improved pull tab mounting arrangement also serves to reduce theprobability that mishandling of the container will result in anunintentional fracture of the score line 4. In the conventional pull tabmounting arrangement (FIG. 3), the nose portion 3a rests in closecontact with the score line 4, such that an accidental impact againstthe nose portion 3a may well result in an unintended fracture of thescore 4. In the improved pull tab mounting (FIG. 1), the nose portion 3ais held in spaced relation above and radially inward of the score line4, such that an accidental impact against the nose portion 3a willresult in the nose portion 3a being forced downward into contact withthe end panel 1, leaving the score 4 unaffected. Further, such anaccidental displacement of the tab 3 will not interfere with thesubsequent opening of the container.

1 claim:

1. An improved pull tab mounting arrangement for a self-opening endclosure for a can or similar container, said end closure comprising anend panel, attachment means formed in said end panel, a pull tabattached by said attachment means to said end panel, and a score lineformed in said end panel and defining an opening flap therein, theimprovement comprising unfoldable means for shiftably mounting saidattachment means in said end panel for relieving stresses on said pulltab and said end panel during lifting movements of said tab for openingof said container.

2. The improved pull tab mounting arrangement as described in claim 1,wherein said unfoldable mounting means unfolds upon commencement of saidopening of said container, thereby displacing the fulcrum point of saidpull tab for enhancing the leverage thereof.

3. The improved pull tab mounting arrangement as described in claim 2,wherein said fulcrum displacing means comprises an expandable pleatformed in said attachment means.

4. The improved pull tab mounting arrangement as described in claim 3,wherein said attachment means comprises a tiltable rivet structure. 1

5. The improved pull tab mounting arrangement as described in claim 2,wherein said stress relieving means comprises expansion means formed insaid attachment means.

6. The improved pull tab mounting arrangement as described in claim 5,wherein said expansion means expands upon stressing thereby relievingstress loading of said end panel and said tab.

7. The improved pull tab mounting arrangement as described in claim 4,wherein said expansion means comprises a single U-shaped pleat formed insaid end panel.

8. The improved pull tab mounting arrangement as described in claim 7,wherein said pleat is concentric with and immediately adjacent to saidrivet.

9. The improved pull tab mounting arrangement as described in claim 8,wherein said pull tab has a nose portion for fracturing said score lineand said nose portion in preopening position is held in spaced relationabove and radially inward of said score line.

10. The improved pull tab mounting arrangement as described in claim 9,wherein said pleat comprises two concentric circular sidewalls dependingfrom said end panel and a substantially U-shaped bight portionconnecting said sidewalls, such that folding of that portion of saidpleat nearest said score line effects simultaneous unfolding of thatportion of said pleat most remote from said score line, consequent toopening said container, results in displacing said pull tab relative tosaid end panel.

11. The improved pull tab mounting arrangement as described in claim 10,wherein said unfolded portion of said pleat everts such that at leastone sidewall of said portion projects outwardly of the plane of said endpanel and said displacement of said tab brings said nose portion intocontact with said score line.

1. An improved pull tab mounting arrangement for a self-opening endclosure for a can or similar container, said end closure comprising anend panel, attachment means formed in said end panel, a pull tabattached by said attachment means to said end panel, and a score lineformed in said end panel and defining an opening flap therein, theimprovement comprising unfoldable means for shiftably mounting saidattachment means in said end panel for relieving stresses on said pulltab and said end panel during lifting movements of said tab for openingof said container.
 2. The improved pull tab mounting arrangement asdescribed in claim 1, wherein said unfoldable mounting means unfoldsupon commencement of said opening of said container, thereby displacingthe fulcrum point of said pull tab for enhancing the leverage thereof.3. The improved pull tab mounting arrangement as described in claim 2,wherein said fulcrum displacing means comprises an expandable pleatformed in said attachment means.
 4. The improved pull tab mountingarrangement as described in claim 3, wherein said attachment meanscomprises a tiltable rivet structure.
 5. The improved pull tab mountingarrangement as described in claim 2, wherein said stress relieving meanscomprises expansion means formed in said attachment means.
 6. Theimproved pull tab mounting arrangement as described in claim 5, whereinsaid expansion means expands upon stressing thereby relieving stressloading of said end panel and said tab.
 7. The improved pull tabmounting arrangement as described in claim 4, wherein said expansionmeans comprises a single U-shaped pleat formed in said end panel.
 8. Theimproved pull tab mounting arrangement as described in claim 7, whereinsaid pleat is concentric with and immediately adjacent to said rivet. 9.The improved pull tab mounting arrangement as described in claim 8,wherein said pull tab has a nose portion for fracturing said score lineand said nose portion in preopening position is held in spaced relationabove and radially inward of said score line.
 10. The improved pull tabmounting arrangement as described in claim 9, wherein said pleatcomprises two concentric circular sidewalls depending from said endpanel and a substantially U-shaped bight portion connecting saidsidewalls, such that folding of that portion of said pleat nearest saidscore line effects simultaneous unfolding of that portion of said pleatmost remote from said score line, consequent to opening said container,results in displacing said pull tab relative to said end panel.
 11. Theimproved pull tab mounting arrangement as described in claim 10, whereinsaid unfolded portion of said pleat everts such that at least onesidewall of said portion projects outwardly of the plane of said endpanel and said displacement of said tab brings said nose portion intocontact with said score line.